"Today is all about the water," Bloomberg rejoiced, praising "McClarren" until the crowd corrected him numerous times and he readjusted his pronunciation to "McCarren."

Bloomberg was joined by Parks Commissioner Adrian Benepe, who stripped down to his bathing suit to hop in the 37,950-square-foot pool, and by Borough President Marty Markowitz, who Bloomberg called "someone who is always in the swim of things in Brooklyn."

Markowitz used the pool's opening as a chance to praise his borough and its "coolest neighborhood," Williamsburg.

"There's no doubt our borough swims laps around the others," he said. "But now Brooklyn just got a lot cooler, literally...If you're looking to stay hip and cool in Brooklyn's coolest neighborhood you know where to go, McCarren."

The newly renovated pool will opened to the public in the afternoon (the morning ribbon-cutting ceremony was only for those who RSVPed to the event) and will be open 11 a.m. — 3 p.m. and 4 p.m. — 7 p.m. daily. The massive pool, which first opened in 1936, has been closed since 1983.

"I learned how to swim in this pool in 1963," recalled Williamsburg Community Board 1 District Manager Gerald Esposito of the old pool. "Now generations to come will have that opportunity."

The pool filled to the brim with eager swimmers all day long, including longtime Williamsburg resident Javier Reyes, 43, who shouted to the crowd, "do you remember the old pool? I do, I do!"

Reyes reminisced about the "two big columns like snow cones" in the previous pool's center that he and his friends would try to climb as children.

"It's a surreal experience, jumping in the water," he said, claiming he would send text messages to all his buddies to brag he had returned to McCarren Pool. "This is the only thing in my lifetime I've seen fall down and be built up again...it's an impossible dream..it's alive again."

A younger local resident, Nina Kearin, 20, said she had also awaited the opening for years.

"I feel like we have our own pool now," said Kearin, floating on her back with her younger brother. "We live right down the street...Our parents moved here the year after they closed the first one."

The pool's neighboring McCarren Rec Center — one of the Parks Department's public gyms and recreational buildings that cost $100 for annual membership — also opened Thursday, and Parks staff gave tours to impressed visitors.

"I could see myself coming here," said Myrna Ortiz, 45, of the rec center, and noted this would be her first membership at a gym.

"We're so glad they brought this all to the neighborhood," said her husband Jaime Ortiz, 45, who grew up in WIlliamsburg. "Now we see where our tax money is going!"

As the crowd at McCarren swam laps, waded in the shallow section, sunbathed, and explored the grounds, a long line snaked down the block throughout the afternoon, since the pool has a limited capacity.

"We didn't expect a line," said Justin Emter, 27, claiming he and his wife waited 45 minutes so she could dip in the water for 10 minutes before they had to dash to a sports game. "My wife loves to swim."

Meanwhile Michelle Sosa, who stood in the line with her family, said she expected to have to wait for entrance to the popular spot.

"This area is so up-and-coming, it's like SoHo," said Sosa, 35, who remarked on the drastic changes since she moved to Williamsburg 16 years earlier. "I'm sure everybody wants to use the pool just like me."

But some visitors walked away when they realized the seemingly endless wait, and they chose to lie in McCarren Park or to go drink in nearby bars instead.

"When I told people we were going to a public pool they were like 'ew,' they thought it would be dirty," said Cheryl Rivera, 21, of Crown Heights. "But it's new and beautiful...we're going to come back tomorrow instead."

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